When you choose a filet of beef in the supermarket, what are you really getting? Here's a review of the eight "grades" that the USDA assigns to meat, plus an explanation of "natural" versus "certified organic" beef and the difference between meat from corn-fed and grass-fed cows.

GRADES OF MEAT

Most of the beef consumed today comes from relatively young animals that are between two and three years old. The animal is most likely either a steer (a castrated bull) or a "fed heifer," a cow that is raised for meat rather than dairy or breeding purposes. In general, the youngest meat is of the highest quality, with a fine texture and a light grayish red color. Older carcasses are coarser and darker red.

"Marbling," or the streaks of fat through the meat, helps determine carcass grade, ranging from what the industry calls "slightly abundant" to "practically devoid." In general, the more marbling a cut of beef has, the more tender and flavorful it will be.

There are eight grades of meat: prime, choice, select, standard, commercial, utility, cutter, and canner. (When buying beef, consumers should look for the USDA shield on the meat package, which denotes that the cuts have been graded by a USDA inspector.) Young beef is categorized as prime, choice, select, and standard, whereas commercial, utility, cutter, and canner grades refer to more mature meat. In most supermarkets, you will find primarily choice and select grades of beef.

Prime, the most rare quality of meat, is not readily available on supermarket shelves. It is served primarily in hotels and restaurants as part of first-rate meals. Heavily marbled with fat, it is the most tender, juicy, and flavorful of beef cuts. It comes from the fattiest, least muscular region of an animal's body, like a loin. Generally, only 3-5 percent of the meat from one head of cattle is considered prime, but that percentage can increase to 50 percent if the amount of time the animal is fattened on corn is doubled. (Cattle are fed corn an average of 120 days.)

Choice is the most prevalent fine-quality consumer beef, followed by select, leaner cuts of beef, which have been gaining in popularity with consumers. Standard and commercial grades of beef are "brand name" or "ungraded," meaning that a supermarket can stamp it with its own label. Utility, cutter, and canner grades are used as ground beef and hot dogs. These are the lowest of the beef grades. Retired dairy or breeding cows are generally slaughtered between 6-8 years of age, and their less tender meat is usually sold ungraded, as ground or otherwise processed product.

From the USDA's Agricultural Marketing Service, this primer explains the different grades of meat and the nutritive values of beef, and provides other consumer tips.

GRASS-FED VS. CORN-FED BEEF

Before the second World War, all American beef was "grass-finished," meaning that cattle ate pasture grass for the duration of their lives. Today, the vast majority of cattle spend anywhere from 60-120 days in feedlots being fattened with grain before being slaughtered. Unless the consumer deliberately chooses grass-finished or "free-range" meat, the beef bought at the grocery store will be of the corn-finished variety.

Feeding corn to cattle in the weeks before slaughter has several advantages for the producer, including:

corn-fed cattle gain weight much more quickly than cattle in a strictly grass-fed environment and can be produced year-round;

the current system of ranching is designed around the accelerated growth of cattle in feedlots, and since corn-fed cattle fit this model, they are easier and more cost-effective to produce, and result in cheaper products for the consumer; and

corn-fed cattle produce the type of meat that American consumers have grown to love and expect: a tasty, marbled, fatty meat with smooth, consistent flavor.

There is a wave of farmers and consumers that argues for a return to the old way of meat production, however. They contend that feeding cattle grass is healthier and more sustainable for both the cow and the consumer.

Rancher Dale Lasater, who raises grass-fed, antibiotic-free cattle, says that his ranching method creates happier animals that are ultimately a better product for the consumer. "From our point of view," says Lasater, "it's simply a very natural, very wholesome way to finish the beef and take them straight from the ranch to the processor."

Meat from a grass-fed steer has about one-half to one-third as much fat as a comparable cut from a grain-fed animal. Lower in calories, grass-fed beef is also higher in vitamin E and omega-3 fatty acids, which are thought to help reduce the risk of cancer, lower the likelihood of high blood pressure, and make people less susceptible to depression. Further, meat from grass-fed cattle is rich in another beneficial fat called conjugated linoleic acid (CLA), which supposedly lowers the risk of cancer. The benefits of CLA are so widely acknowledged that some ranchers who don't grass-finish their cattle add CLA supplements to their animals' feed once they're taken to the feedlots.

Eat Wild bills itself as "the clearinghouse for information about pasture-based farming." Through its suppliers list, visitors can find the producers in their state that sell grass-fed beef products.

NATURAL AND ORGANIC BEEF

Some consumers who are concerned about the environment and additives to food, as well as the health and well-being of cattle, are choosing to buy meat that is labeled "natural" or "organic." Before deciding whether one of those labels is the right choice, it is important to know what the label means.

There is no clear standard for "natural" beef. According to the USDA, natural beef is that which is "minimally processed and contains no artificial ingredients." The obvious problem with such a loose definition is that, for the consumer, there is no way to be sure that meat labeled natural comes from cattle that have been raised in a wholesome environment. There are so-called "animal production claims," which, as long as they are demonstrably true, have been approved by the USDA's Food Safety and Inspection Service (FSIS). Claims such as "No Hormone Implants Used in Raising" and "Raised In An Open Pasture" are fairly clear, however.

"Certified organic" labels on beef are more clearly defined.

Congress passed the Organic Foods Production Act of 1990 but the USDA's Agricultural Marketing Service and the National Organic Program are still in the process of developing regulations for the use of the term "organic" on the labeling of food products. Under the current system, farmers petition the FSIS for the right to call their produce and animals "certified organic." Producers must submit affidavits of handling and proof of having met certain production standards. The primary factors involved in certifying organic meat at this time are that the animals must be raised on organic feed without pesticides, and must be raised without hormones and antibiotics. All organic farmers must be certified by USDA-accredited agents by Oct. 21, 2002.